Microwave Staring Correlated Imaging Based On Multi-receivers

Single-receiver Microwave staring correlated imaging(MSCI)based on temporal-spatial stochastic radiation field(TSSRF)has got a great achievement after several years' development.But the restriction of real system aperture,number of radiating elements and other factors,such as signal bandwidth limits,make the MSCI model ill-posed,thus the imaging process is sensitive to noise and take a long time.To solve the above problem,this paper puts forward with multi-receivers MSCI,the spatial spread of which is utilized to improve the ill-posedness of single-receiver MSCI model,so as to increase the robustness of imaging process to noise and shorten the imaging time.The main research work includes:On the foundation of single-receiver MSCI principal,this paper established multiple-receivers MSCI model based on fusion of the dimension-extended data layer.Through analysis of the correlation between random radiation field of multi-point observation samples,we proves that the multiple receivers can increase effective observation samples,and we also propose a method of using the effective rank of stochastic radiation field matrix to quantitatively characterize effectiveness of a set of stochastic radiation field samples.The optimization method based on maximization of effective rank of stochastic radiation field matrix lead to a problem that the calculating of objective function is too complex and the efficiency is too low,so we propose the optimization method based on maximization of spatial distribution entropy instead.At first,we utilize spatial distribution entropy to quantitatively characterize the randomness of transceivers distribution by which we analyze and verify the total positive correlation between spatial distribution entropy and the effective rank of stochastic radiation field.Secondly we establish the optimization model of the arrangement of transceivers based on maximization of spatial distribution entropy,and then we optimize the distribution of transceivers by taking advantage of genetic algorithm.At last,we verified that the transceivers layout optimization can improve MSCI performance by numerical simulation.The construction of orthogonal radiation field is studied.Compared with constructing random radiation field forwardly by random signal modulation,random transceivers distribution and the like,this paper purpose a method to inversely construct orthogonal radiation field.At first,we use a set of two-dimensional spatial orthogonal basis functions to characterize the specific distribution of the ideal orthogonal radiation field.Then we obtained a set of approximate orthogonal radiation field samples by reasonably designing of excitation signal of radiating elements to approach ideal radiation field samples.We verify the effectiveness of this method by numerical simulation.Finally,we show that the robustness of imaging procession to noise got improved,when orthogonal radiation is used for MSCI.In order to enhance the imaging speed,this paper proposes a sequential processing method of multi-receivers MSCI.This method is constructed based on sequential least squares real-time echo data processing model.Because of reducing the dimensions of matrix inversion,this method can accelerate the imaging procession.The simulation show the effectiveness of this method.